Shape evolution of alpha-Fe2O3 and its size-dependent electrochemical properties for lithium-ion batteries

Crystalline alpha-Fe2O3 with different particle shapes and sizes was selectively synthesized by a simple hydrothermal method. By carefully tuning the concentration of the reactants and the reaction time, alpha-Fe2O3 cuboid particles and nanowires can be obtained. Based on the evidence of electron microscope images, a shape evolution mechanism for the nanowire structure is proposed. Electrochemical performance as an anode material for lithium-ion batteries was further evaluated by cyclic voltammetry, electro-chemical impedance, and charge-discharge measurements. It was demonstrated that both the morphology and the particle size had an influence on the performance. Compared with the electrode made from the cuboid material, the nanowire electrode displayed higher discharge capacity and better cycling reversibility, which may be a result of the one-dimensional nanostructure and high surface area. (C) 2008 The Electrochemical Society.